Journal of Dental Research, Vol 66, 1559-1562, Copyright © 1987 by International & American Associations for Dental Research Online Journals
Lumen formation during development of the rat submandibular gland
L. S. Cutler and B. A. Mooradian
This study utilized electron microscopy and enzyme histochemistry to
examine the morphological steps associated with the formation of a lumen in
the end-buds of the embryonic rat submandibular gland. Lumen formation
involved the development of junctional complexes by the central cells of
the end-buds late on the 16th day of gestation. These junctional complexes
established the apical domains of the presecretory cells, and cytofilament
aggregates were observed beneath the presumptive luminal plasma membranes.
This central area of the end-buds showed strong myosin ATPase activity,
presumably associated with the cytofilaments. On the 17th day of gestation,
small lumina appeared at the sites delineated by the junctional complexes.
The myosin ATPase activity appeared to surround the newly opened lumina. By
the 18th day of gestation, microvilli were seen projecting into the lumina,
and secretory granules were often visible in the apical cytoplasm near the
luminal plasma membranes of the early secretory cells. Myosin ATPase
activity was greatly reduced once the lumina had formed.
